From: Compania Panamena de Aviacion, S.A.

To: [ ] [Date]

Dear Sirs,

We acknowledge receipt of a Notice of Assignment dated [ ] (the "Assignment
Notice") relating to an assignment (the "Assignment") between Wells Fargo Bank
Northwest, N.A., not in its individual capacity, but solely as trustee under the
Trust Agreement (the "Assignor"), and you. [Subject to the fulfillment or
satisfaction of the requirements of Clause 14.2 of the Lease and your agreement
in our favor to be bound by the obligations of Lessor as set forth in and in
accordance with the Lease and further subject to the receipt of a Quiet
Enjoyment Letter in the form attached hereto and to your counter-signature and
that of Assignor hereof,] we acknowledge that we will not challenge the
effectiveness of the Assignment to confer on you all rights, title and interest
of the Assignor under the Aircraft Lease Agreement dated as of December 23, 2004
between Assignor and ourselves (the "Lease") in respect of one Boeing B[ ]
aircraft with manufacturer's serial number [ ] together with the two [ ]
engines.

In consideration of the foregoing and of payment to us of $1 and for other
valuable consideration, receipt of which we hereby acknowledge, we hereby agree
as follows: